1. Field of the Invention
This invention relates to adjustable seats, and particularly to arm chairs having seat cushions that can be adjusted forward and aft to comfortably support persons of differing size and stature.
2. Background Art
Because of the need to accommodate persons of differing size and stature, adjustable seats have been developed and installed in a wide variety of seating environments, such as dentists"" chairs, barbers"" chairs, easy chairs, and motor vehicles. In the case of motor vehicles, adjustable seats have been either of the manually adjustable kind, or electrically powered. In the case of manually adjustable, front seats installed in motor vehicles, fore and aft adjustments of the seat cushion were performed by sliding the entire seat fore and aft along floor-mounted tracks; no provision was made for varying the front-to-rear dimensions of the seat cushions themselves. Electrically powered, adjustable front seats for motor vehicles typically permit a wider range of seat adjustments than manual versions. See, for instance, U.S. Pat. No. 5,553,920 to R. Meschkat et al.; and see especially U.S. Pat. No. 5,171,062 to B. Courtois, which disclosed an electrically powered adjustable front seat for a motor vehicle that permitted varying the front-to-rear dimension of the sitting portion of the seat.
Manually adjustable seating has distinct advantages over electrically powered adjustable seating for residential applications. Manual adjustment obviates the need for supplying electrical power to an adjustable easy chair, thereby permitting greater choice and flexibility in arranging furniture for a desired residential floor plan or interior decoration scheme. A manual adjustment mechanism, compared to an electrically powered adjustment mechanism, simplifies assembly and repair, reduces manufacturing cost, and lessens the weight of the chair. U.S. Pat. No. 3,007,738 to R. Gardel, et al., disclosed a manually adjustable chair that permitted varying the front-to-rear dimension of the sitting surface by providing a flexible extension leg rest that was fore-and-aft slidable on a pair of channel-shaped tracks. The tracks extended rearwardly and upwardly along the sides of the chair back, such that, when the leg rest was moved aft to a retracted position, it would slide up inside a hollow space within the chair back. For an easy chair, however, this arrangement is unsatisfactory because the relatively large and thick seat cushion of an easy chair would require an excessively large and bulky hollow space within the chair back. Moreover, it requires more upper body strength than some elderly or infirm persons can muster to be able to force an object as large and heavy as a seat cushion up inside a seat back.
There remains a need, therefore, for a manual seat cushion adjustment apparatus for an easy chair that permits fore-and-aft adjustment of the seat cushion to accommodate persons of differing size and stature. This need is fulfilled by the present invention.
A manual seat cushion adjustment apparatus is provided for a chair equipped with a pair of spaced-apart, vertical frame supports, a seat back laterally disposed between, and extending above, rear portions of the frame supports, and a flexible seat cushion. The apparatus permits fore and aft movements of the seat cushion, thereby varying the front-to-rear dimension of the sitting portion of the chair to comfortably accommodate persons of differing size and stature. The flexible cushion rests upon a carriage assembly. The carriage assembly is laterally disposed between the frame supports and is longitudinally movable, fore and aft, between a first, extended position and a second, retracted position. A carriage assembly support means is laterally disposed between, and attached to, the frame supports, for supporting the carriage assembly and permitting longitudinal movements thereof. Manual means is attached to the carriage assembly support means for reversibly locking the carriage assembly in any one of a plurality of longitudinally spaced-apart positions.
In a preferred embodiment, the carriage assembly includes a pair of horizontal, longitudinally-extended, laterally spaced-apart side rails. A carriage base extends between, and joins, the side rails. A straight, longitudinally-extended, fixed track is attached to, and extends along an entire lower surface of each of the side rails. A pliable track is aligned and continuous with each fixed track and extends rearwardly and downwardly thereof. A plurality of transversely elongated, rectangular slats extend laterally between, and are attached to, the pliable tracks. A laterally-disposed header joins front portions of the side rails. The carriage assembly support means includes a horizontal, rectangular support panel disposed between, and joining, the frame supports. A pair of longitudinally-extended, laterally spaced-apart channels are mounted on an upper surface of the support panel. The channels are adapted to receive and retain the fixed and pliable tracks in sliding engagement. Each of the channels has a rear portion that extends rearwardly and downwardly from the support panel for receiving and retaining the pliable tracks in sliding engagement. Each of the channels has a U-shaped lateral cross-section, and each of the fixed and pliable tracks has an I-shaped, lateral cross section.
The pliable tracks can be fabricated from some suitably pliable material. In a preferred embodiment, however, pliability is provided by incorporating into each pliable track a series of alternating upper and lower links, hingedly connected to each other so as to permit vertical rotation of each link with respect to adjacent links. Each upper link has a first, laterally-disposed downturned, rolled edge, and a second, oppositely-directed, laterally-disposed, downturned, rolled edge. Each lower link has a first and second upturned, rolled edges that partially surround the downturned edges of adjacent upper links. A hinge pin is inserted through each of the first and second rolled edges of the upper links.
The manual means for locking the carriage assembly preferably includes a bale having a pair of laterally spaced-apart, longitudinally-directed stringers joined at a forward end thereof by a laterally disposed bight portion. The bale is preferably formed by bending metal rod or wire. Each of the stringers has a straight, front portion, disposed adjacent a side rail, and a straight rear portion that is vertically displaced with respect to the front portion. Each of the rear portions of the bale stringers terminate in an upturned hook end. A pivot arm joins the front portion to the rear portion of each stringer, and maintains the vertical displacement between them. Means attached to the side rails are provided for pivoting the pivot arm about a horizontal, lateral axis. A handle extends forwardly from the bight portion of the bale through an opening in the header. A spring is disposed adjacent the opening in the header for urging the bight portion of the bale downward, thereby urging the hook ends upward. Detent means are attached to the support panel for receiving and retaining the upturned hook ends of the bail in any of a plurality of longitudinally-separated positions. Vertical displacement of the handle withdraws the hook ends from the detent means, which permit fore and aft movements of the carriage assembly and seat cushions. Once the seat cushion is in a new, desired position, the handle is released, whereby the hook ends insert into the detent means at a new location therein, locking the carriage assembly and seat cushion in place. An opening is provided between a lower portion of the seat back and the back of the chair in order to permit free fore and aft movements of the carriage assembly and seat cushion.